By now we've covered all sorts of goodies that make car audio a more fun experience. We've hit on speakers that make car audio possible, subwoofers that deliver deep bass and inputs that enhance the listening experience. Now we'll take a look at how to make it all sound even better.
Subwoofers require amplifiers to deliver those low frequency sounds. Amplifiers work by boosting an audio signal into something powerful enough for the speakers to output. Think of an amp like a high-tech megaphone: Your mouth is the audio input from the radio/CD/MP3 player, the megaphone is an amplifier connected to your speakers, and the loud voice coming out of the megaphone is the sound your speakers can produce. Speaker systems need amplifiers to work, which means your car already has one, just like it has basic speakers built in.
But if you plan on expanding your car audio system with nice component speakers and a subwoofer, an aftermarket amplifier is a must. The power will give your audio new life; in fact, without a new amplifier, your audio system probably won't work at all. Each speaker needs an audio channel; while a two-channel amplifier would work for a two-way component speaker setup or a two-way coaxial speaker, you need more channels if you plan on adding more speakers to the component setup. And, of course the subwoofer needs its own channel. Amplifiers with four or more channels will work with a subwoofer and component speaker arrangement [source: ABT].
When choosing an amplifier, there are two ratings to pay attention to: RMS and peak power. RMS power refers to the amount of continuous power applied to the amp, while peak power rates how much power an amp can deliver during an especially loud moment. Think of RMS power as a steady rhythm, key to maintaining quality sound over the long term. Peak power is like a blaring trumpet blast: You want it to be as powerful as possible, but it's less indicative of the overall performance of the system [source: Crutchfield]. With an amplifier and all those speakers in place, there's still one key element missing: the crossover.